1. Field
This disclosure relates generally to semiconductor devices, and more specifically, to semiconductor devices with integrated resistive elements and methods of making the same.
2. Related Art
As device dimensions shrink, high dielectric constant (high-k or hi-k) materials are being considered for use as the gate dielectric for devices operating at the lowest voltages in a corresponding integrated circuit, henceforth referred to as core devices. However, problems exist if a high-k material, such as HfO2 (hafnium oxide), is used for high voltage devices, such as an intermediate thickness gate oxide devices (henceforth known as TGO devices), a thicker gate oxide devices (henceforth known as DGO devices), or capacitors on the integrated circuit. For example, if HfO2 is formed over SiO2 (silicon dioxide), the Hf (hafnium) and Hf-induced defects may diffuse into the SiO2 during manufacturing. The diffusion will cause poor reliability, especially in high voltage applications. In addition, using a high-k material changes the work function of the device. When the work function changes, the technology associated with the device must be typically altered, which consumes time and resources by having to develop new technology. Furthermore, it is unknown if any effects due to interaction between the high-k material and other materials at the edge of a patterned gate are created when using HfO2 in a high voltage device.
Integrated circuit passive devices traditionally include polysilicon resistors. One example of forming a polysilicon resistor includes doping polysilicon to control its resistance. As indicated herein above, as integrated circuit device dimensions shrink, transistor devices are migrating to high-K dielectrics and metal gate transistors. However, added complexities and increased manufacturing costs are incurred with respect to the formation of polysilicon passive devices with the high-K dielectric and metal gate transistor devices. In other words, the traditional approaches in the formation of polysilicon passive devices are no longer suitable for use with high-K dielectric and metal gate transistor technology.
Accordingly, there is a need for an improved method and apparatus for overcoming the problems in the art as discussed above.